Double depth selectively firing mechanism for a depth charge



April 26, 1960 s. BURG 2,934,012

DOUBLE DEPTH SELECTIVELY FIRING MECHANISM FOR A DEPTH CHARGE Filed Dec. 18, 1957 2 Sheets-Sheet 1 m Q N O G L n/ g Q! ruo \i 5 Ll- O :I Q 3 I u- D l/ INVENTOR. SOLOMON BURG a I BY Z ATTYS.

April 26, 1960 s. BURG 2,934,012

DOUBLE DEPTH SELECTIVELY FIRING MECHANISM FOR A DEPTH CHARGE Filed Dec. 18, 1957 2 Sheets-Sheet 2 INVENTOR. 3L SOLOMON BURG wlmm 2 BY ,Z/JL

United States Patent DOUBLE DEPTH SELECTWELY FIRING MECH- ANISM F OR A DEPTH CHARGE Solomon Burg, Kensington, Md.

Application December 18, 1957, Serial No. 703,715

4 Claims. (Cl. 10216) (Granted under Title 35, US. Code (1952), sec. 2.66)

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

This invention relates to the firing mechanism for a depth charge and more particularly to a double depth selecting firing mechanism operated by hydrostatic pressure when the pressure has increased to a predetermined selected value.

In devices of this character heretofore proposed it has been the usual practice to provide a diaphragm in communication with the surrounding water which is maintained in an initial position by a spring, the diaphragm being actuated by the pressure of the water on one side thereof to a firing position against the pressure of the spring when the depth charge has sunk to a predetermined depth such, for example, as fifty feet. By employing a heavier spring, it has been found possible to extend the depth at which the depth charge is fired to a depth of approximately two hundred feet. Modern submarines are now capable of submerging to a much greater depth, such, for example, as three hundred to four hundred feet. Such a depth is beyond the operating capabilities of these prior art devices which vary their depth setting by variations in the tension of the biasing spring alone.

The devices of the present invention possesses all of the advantageous qualities of the prior art device and none of the foregoing disadvantages. This is accomplished in accordance with a preferred form of the invention by selectively equalizing the hydrostatic pressure over a portion of the diaphragm when the firing device is to be employed for operation at the greater one of the two selectable depth ranges and a portion of the diaphragm externally exposed to the sea water is thus without effect. With this arrangement the useful effective portion of the diaphragm requires a greater hydrostatic pressure thereagainst to effect the operation of the device as will more clearly appear as the description proceeds.

One of the objects of the present invention is to provide a firing mechanism for a depth charge having new and improved means for selecting at will one of two depth ranges at which the depth charge is to be fired.

Another object is to provide a hydrostatically controlled depth charge firing mechanism having new and improved means for selecting at will the depth at which the mechanism operates.

Other objects, advantages and improvements will become more clearly apparent from the following description taken in connection with the accompanying drawings of which:

Fig. 1 is a view of a depth charge employing the device of the present invention according to a preferred embodiment thereof;

Fig. 2 is a view somewhat enlarged and partially in section of the firing mechanism of Fig. l; and

Fig. 3 is ,an enlarged view in section of the hydrostatical- 1y actuated means for operating the firing mechanism and on which is shown the depth selecting device employed therewith.

Referring now to the drawings for a more complete understanding of the invention on which like numerals of reference are employed to designate like or similar parts throughout the several views and more particularly to Fig. 1 thereof, there is shown thereon a depth charge indicated generally by the numeral 10 comprising an up standing tubular casing 11 having a support 12 secured thereto in any suitable manner as by threading the parts together. Carried by the support 12 is a cap 13 threaded thereon as shown and sealed as by a gasket 14, Fig. 3. A circular diaphragm 15 composed of resilient material suitable for the purpose such for example as rubber or any of the synthetic varieties thereof, is arranged in abut-.

a plurality of apertures 21 for establishing communicationv between the chamber and the surrounding water when the depth charge has been launched. Preferably though not necessarily the depth charge is provided with a tail structure 22 comprising a plurality of fins'23 threadedly secured to the cap 13 by the screw 24 substantially as shown thereby to provide air stability for the depth charge during its flight through the air whether from an -aircraft in flight or from an ahead-thrown weapon, as the case may be, and to additionally provide water stability thereto during the descent of the depth charge through the water.

A plunger 25 is slidably disposed within a bore 26 formed within support 12 and provided with a conical end portion 27 and an 0 ring seal 20. The other end of the plunger is provided with a head 28 of lesser crosssection than the area defined by the inner circular portion of surface 16. The plunger 25 also carries a shoulder or flange 29, for engagement with one end of spring 31, the other end of the spring 'being engaged by shoulder 32 formed in the bottom of bore 33 within support 12. An arrangement is thus provided in which the diaphragm 15 is normally urged into snug abutting engagement with the innner surface of circular stop 17 by the spring 31 until the pressure of the water against the diaphragm is sufficient to cause plunger 25 to be moved inwardly therefrom. Bore 33, it will be noted, is contiguous with bore 34 which is enlarged at 35 to form a chamber indicated generally at 36. Communicating with chamber 36 is a duct 37 threaded at 38 to receive a plug or screw 39 sealed thereto in any suitable manner as by the .O-ring 41 and thereby providing a water stop.

The tubular casing is threaded to a support 42, Fig. 2, having a bore therein, within which is slidably disposed a firing pin 43 having a shoulder 44 thereon engaged by a spring 45, the other end of the spring being in engagement with shoulder 46 formed within the support 42. As most clearly shown on Fig. 2, the firing pin is maintained in a cocked position by a pair of latch members 47 pivoted at 48 to the support 42 for movement within a slot formed in the support. The latch members are provided with two latching elements 49 for engagement with a complementary circular shoulder 51 formed on the firing pin 43 in such manner that the firing pin is maintained in a cocked position with spring 45 under compres sion until the latch members 47 are moved apart by the pointed end 27 of plunger 25 as the plunger is moved inwardly by the pressure of the water to a firing position. The upper end of each of the latching elements Patented Apr. 26, 1960 is preferably rounded at 52 to provide a cam surface for engagement with the conical end portion 27 of the plunger 25. The latching elements are preferably held in the latched position in any suitable manner as by the flexible O-ring 53 illustrated or, if desired, a circular helical spring may be employed in lieu of the old O-ring. As the firing pin is unlatched, the pointed inner end 54 thereof engages the detonator illustrated schematically at 55 thereby firing the depth charge.

When it is desired to employ the depth charge firing mechanism for use with a target submerged at a first depth range such, for example, as a depth of fifty feet, the plug 39 is inserted into the threaded bore 38 thereby closing duct 37. The water is thus prevented from entering chamber 36 and the depth charge, therefore, in the assumed example, is fired when it has sunk to a depth of fifty feet within the water.

In the event, however, it is desired to employ the firing mechanism of the present invention with a target submerged to a depth within the second depth range such as depth of 300400 feet, the plug 39 is removed thereby opening duct 37 for communication with the surrounding water. As the depth charge sinks within the water, water enters chamber 36 by way of duct 37 such that the pressure of the water is applied to both sides of the diaphragm. An arrangement is thus provided whereby the internal hydrostatic pressure per unit area applied to the diaphragm is equal and opposite to the external pressure per unit area applied by the Water thereto. The effective unit area of the inside surface of the diaphragm is reduced by the cross sectional area of the plunger and the only effective portion of the diaphragm therefore is that portion defined by the area of the plunger which obviously is less than the total area of the exterior surface of the diaphragm. The plunger 25, therefore, is moved to a firing position in response to a hydrostatic pressure against the exterior portion of the diaphragm corresponding to a depth of 300-400 f eet.

From the foregoing, it will be clearly apparent that there has been provided a depth charge firing mechanism in which new and improved means are employed for changing at will the depth setting of the device from a setting Within a first depth range whereby the entire exterior surface of the diaphragm is employed to fire the depth charge to a setting within a second depth range wherein only a fractional portion of the exterior surface of the diaphragm is effective to fire the depth charge.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

l. A hydrostatically operated device for firing a depth charge comprising a fiexible diaphragm having the outer surface in communication with the surrounding water, a

plunger engaged by a central portion of said diaphragm and having a firing pin operable thereby, a casing enclosing the inner surface of the diaphragm to which the diaphragm is sealed, means for slideably sealing the plunger to the casing, means yieldably urging the plunger against the diaphragm, and means operable at will for selectively establishing fixed water communication to the interior of said casing prior to the launching of the depth charge.

2. A depth charge firing device according to claim 1 in which the cross-sectional area of said plunger is less than the outer surface area of said diaphragm.

3. A hydrostatically operated device for firing an explosive as the device sinks within the water comprising, in combination, a casing, a plunger slideably sealed to said casing and movable from an initial position to a firing position, a flexible diaphragm having the central portion thereof engaged by said plunger and sealed to said casing in such manner that the exterior of the diaphragm is exposed to the surrounding water, means forming a chamber withinsaid casing sealed jointly by said diaphragm and the plunger, a helical spring for yieldably urging the plunger in said initial position, a head on said plunger for establishing an operative connection between the plunger and the diaphragm, and water stop means operable at will prior to launching of the device for selectively establishing fixed communication between the surrounding water-and the interior of said chamber whereby the efiective area of said diaphragm in communication with the water is reduced from the entire exterior area of the diaphragm to a fractional portion thereof corresponding in size to the cross sectional area of said plunger when said communication is established.

4. A depth charge firing mechanism of the character disclosed comprising a diaphragm normally exposed at the outer surface thereof to the surrounding water, means forming a chamber normally excluding Water from the other side of said diaphragm, a spring-urged plunger engaged by a central portion of the diaphragm and adapted to be operated from an initial position to a firing position thereby, said plunger being slideable within said means forming the chamber, and means for selectively admitting water to the interior of said chamber prior to launching of the depth charge thereby to apply water pressure continuously and equally to both sides of the diaphragm and reduce the effective operating surface thereof to the cross-sectional area of said plunger when the water has been admitted to the interior of the chamber regardless of the depth of submersion of the mechamsm.

References Cited in the file of this patent UNITED STATES PATENTS 1,314,665 Huber Sept. 2, 1919 1,639,665 Pratt Aug. 23, 1927 2,438,117 Ellwood Mar. 23, 1948 

